#include "git-compat-util.h"

#include "config.h"

#include "gettext.h"

#include "repository.h"

#include "fsmonitor-ipc.h"

#include "fsmonitor-settings.h"

#include "fsmonitor-path-utils.h"

/*

 * We keep this structure defintion private and have getters

 * for all fields so that we can lazy load it as needed.

 */

struct fsmonitor_settings {

  enum fsmonitor_mode mode;

  enum fsmonitor_reason reason;

  char *hook_path;

};

/*

 * Remote working directories are problematic for FSMonitor.

 *

 * The underlying file system on the server machine and/or the remote

 * mount type dictates whether notification events are available at

 * all to remote client machines.

 *

 * Kernel differences between the server and client machines also

 * dictate the how (buffering, frequency, de-dup) the events are

 * delivered to client machine processes.

 *

 * A client machine (such as a laptop) may choose to suspend/resume

 * and it is unclear (without lots of testing) whether the watcher can

 * resync after a resume.  We might be able to treat this as a normal

 * "events were dropped by the kernel" event and do our normal "flush

 * and resync" --or-- we might need to close the existing (zombie?)

 * notification fd and create a new one.

 *

 * In theory, the above issues need to be addressed whether we are

 * using the Hook or IPC API.

 *

 * So (for now at least), mark remote working directories as

 * incompatible unless 'fsmonitor.allowRemote' is true.

 *

 */

#ifdef HAVE_FSMONITOR_OS_SETTINGS

static enum fsmonitor_reason check_remote(struct repository *r)

{

  int allow_remote = -1; /* -1 unset, 0 not allowed, 1 allowed */

  int is_remote = fsmonitor__is_fs_remote(r->worktree);

  switch (is_remote) {

    case 0:

      return FSMONITOR_REASON_OK;

    case 1:

      repo_config_get_bool(r, "fsmonitor.allowremote", &allow_remote);

      if (allow_remote < 1)

        return FSMONITOR_REASON_REMOTE;

      else

        return FSMONITOR_REASON_OK;

    default:

      return FSMONITOR_REASON_ERROR;

  }

}

#endif

static enum fsmonitor_reason check_for_incompatible(struct repository *r,

                int ipc MAYBE_UNUSED)

{

  if (!r->worktree) {

    /*

     * Bare repositories don't have a working directory and

     * therefore have nothing to watch.

     */

    return FSMONITOR_REASON_BARE;

  }

#ifdef HAVE_FSMONITOR_OS_SETTINGS

  {

    enum fsmonitor_reason reason;

    reason = check_remote(r);

    if (reason != FSMONITOR_REASON_OK)

      return reason;

    reason = fsm_os__incompatible(r, ipc);

    if (reason != FSMONITOR_REASON_OK)

      return reason;

  }

#endif

  return FSMONITOR_REASON_OK;

}

static struct fsmonitor_settings *alloc_settings(void)

{

  struct fsmonitor_settings *s;

  CALLOC_ARRAY(s, 1);

  s->mode = FSMONITOR_MODE_DISABLED;

  s->reason = FSMONITOR_REASON_UNTESTED;

  return s;

}

static void lookup_fsmonitor_settings(struct repository *r)

{

  const char *const_str;

  char *to_free = NULL;

  int bool_value;

  if (r->settings.fsmonitor)

    return;

  /*

   * Overload the existing "core.fsmonitor" config setting (which

   * has historically been either unset or a hook pathname) to

   * now allow a boolean value to enable the builtin FSMonitor

   * or to turn everything off.  (This does imply that you can't

   * use a hook script named "true" or "false", but that's OK.)

   */

  switch (repo_config_get_maybe_bool(r, "core.fsmonitor", &bool_value)) {

  case 0: /* config value was set to <bool> */

    if (bool_value)

      fsm_settings__set_ipc(r);

    else

      fsm_settings__set_disabled(r);

    return;

  case 1: /* config value was unset */

    const_str = getenv("GIT_TEST_FSMONITOR");

    break;

  case -1: /* config value set to an arbitrary string */

    if (repo_config_get_pathname(r, "core.fsmonitor", &to_free))

      return; /* should not happen */

    const_str = to_free;

    break;

  default: /* should not happen */

    return;

  }

  if (const_str && *const_str)

    fsm_settings__set_hook(r, const_str);

  else

    fsm_settings__set_disabled(r);

  free(to_free);

}

enum fsmonitor_mode fsm_settings__get_mode(struct repository *r)

{

  if (!r->settings.fsmonitor)

    lookup_fsmonitor_settings(r);

  return r->settings.fsmonitor->mode;

}

const char *fsm_settings__get_hook_path(struct repository *r)

{

  if (!r->settings.fsmonitor)

    lookup_fsmonitor_settings(r);

  return r->settings.fsmonitor->hook_path;

}

void fsm_settings__set_ipc(struct repository *r)

{

  enum fsmonitor_reason reason = check_for_incompatible(r, 1);

  if (reason != FSMONITOR_REASON_OK) {

    fsm_settings__set_incompatible(r, reason);

    return;

  }

  /*

   * Caller requested IPC explicitly, so avoid (possibly

   * recursive) config lookup.

   */

  if (!r->settings.fsmonitor)

    r->settings.fsmonitor = alloc_settings();

  r->settings.fsmonitor->mode = FSMONITOR_MODE_IPC;

  r->settings.fsmonitor->reason = reason;

  FREE_AND_NULL(r->settings.fsmonitor->hook_path);

}

void fsm_settings__set_hook(struct repository *r, const char *path)

{

  enum fsmonitor_reason reason = check_for_incompatible(r, 0);

  if (reason != FSMONITOR_REASON_OK) {

    fsm_settings__set_incompatible(r, reason);

    return;

  }

  /*

   * Caller requested hook explicitly, so avoid (possibly

   * recursive) config lookup.

   */

  if (!r->settings.fsmonitor)

    r->settings.fsmonitor = alloc_settings();

  r->settings.fsmonitor->mode = FSMONITOR_MODE_HOOK;

  r->settings.fsmonitor->reason = reason;

  FREE_AND_NULL(r->settings.fsmonitor->hook_path);

  r->settings.fsmonitor->hook_path = strdup(path);

}

void fsm_settings__set_disabled(struct repository *r)

{

  if (!r->settings.fsmonitor)

    r->settings.fsmonitor = alloc_settings();

  r->settings.fsmonitor->mode = FSMONITOR_MODE_DISABLED;

  r->settings.fsmonitor->reason = FSMONITOR_REASON_OK;

  FREE_AND_NULL(r->settings.fsmonitor->hook_path);

}

void fsm_settings__set_incompatible(struct repository *r,

            enum fsmonitor_reason reason)

{

  if (!r->settings.fsmonitor)

    r->settings.fsmonitor = alloc_settings();

  r->settings.fsmonitor->mode = FSMONITOR_MODE_INCOMPATIBLE;

  r->settings.fsmonitor->reason = reason;

  FREE_AND_NULL(r->settings.fsmonitor->hook_path);

}

enum fsmonitor_reason fsm_settings__get_reason(struct repository *r)

{

  if (!r->settings.fsmonitor)

    lookup_fsmonitor_settings(r);

  return r->settings.fsmonitor->reason;

}

char *fsm_settings__get_incompatible_msg(struct repository *r,

           enum fsmonitor_reason reason)

{

  struct strbuf msg = STRBUF_INIT;

  const char *socket_dir;

  switch (reason) {

  case FSMONITOR_REASON_UNTESTED:

  case FSMONITOR_REASON_OK:

    goto done;

  case FSMONITOR_REASON_BARE: {

    char *cwd = xgetcwd();

    strbuf_addf(&msg,

          _("bare repository '%s' is incompatible with fsmonitor"),

          cwd);

    free(cwd);

    goto done;

  }

  case FSMONITOR_REASON_ERROR:

    strbuf_addf(&msg,

          _("repository '%s' is incompatible with fsmonitor due to errors"),

          r->worktree);

    goto done;

  case FSMONITOR_REASON_REMOTE:

    strbuf_addf(&msg,

          _("remote repository '%s' is incompatible with fsmonitor"),

          r->worktree);

    goto done;

  case FSMONITOR_REASON_VFS4GIT:

    strbuf_addf(&msg,

          _("virtual repository '%s' is incompatible with fsmonitor"),

          r->worktree);

    goto done;

  case FSMONITOR_REASON_NOSOCKETS:

    socket_dir = dirname((char *)fsmonitor_ipc__get_path(r));

    strbuf_addf(&msg,

          _("socket directory '%s' is incompatible with fsmonitor due"

            " to lack of Unix sockets support"),

          socket_dir);

    goto done;

  }

  BUG("Unhandled case in fsm_settings__get_incompatible_msg: '%d'",

      reason);

done:

  return strbuf_detach(&msg, NULL);

}